Gsm Rx Tunings - Nokia RH-13 Series Troubleshooting Manual

CCS Technical Documentation

GSM RX tunings

LP and AMP2 filters tunings
- This is done using Safari internal loop. No external signal is needed
If it fails there can be following problems:
- Safari problem
GSM AFC tuning
- Purpose of the tuning is to correct phone frequency error
If AFC tuníng fails it might be due to:
- Problems with upper band signal path (synthesizer etc.)
- VCTCXO component can be broken
- (UEM)
- (UPP)
GSM UB LNA GAIN AND RSSI OFFSET
- UB GSM reference gain (around 74 dB), measured when lna is switched off
- UB LNA gain step, measured when lna is switched on. Result is gain difference between
lna on and off (around 21 dB)
If it fails there can be following problems:
- Rx chain is totally deaf or some gain is missing, start receiver troubleshooting
GSM LB LNA GAIN AND RSSI OFFSET
- UB GSM reference gain (around 77 dB), measured when lna is switched off
- UB LNA gain step, measured when lna is switched on. Result is gain difference between
lna on and off (around 20 dB)
If it fails there can be following problems:
- Rx chain is totally deaf or some gain is missing, start receiver troubleshooting
RX temperature calibration
- NTC resistor calibration in ambient temperature
Issue 1 11/02 ãNokia Corporation
RH-13
Troubleshooting
Page 73